Electron-discharge apparatus



May 18 192 6.

S. L. CLOTHIER ELECTRON DISCHARGE APPARATUS Filed May 29, 1924 InventorStewart, .C|othier-;

His Attorney l atented May 1926.

' UNITEDI STATES PATEN STEWART L. CLOTHIER, OF :SOHENECTADY, NEW YORK;FRANK 'S. .CLOTHIER, GUARD- i,5s5,464 OFFICE.

' IAN OF SAID STEWART L. CLOTHIER; ASSIGNOR'TO GENERAL ELECTRIC COMPANY,

A CORPORATION OF NEW YORK.

ELECTRON-DISCHARGE APPARATUS. i I.

. 5 trodes.

One of the objects of my invention is to provide an improved circuitorganization for use with adevice of the type mentioned whereby theamplification which may be obtained with such a device may be increased.

In connection with electron discharge devices of the thermionic typehaving a grid for controlling the flow of current between cathode andanode it has been proposed to employ a second grid between the cathodeand control grid, and to impress upon this second grida constantpositive potential somewhat lower than that of-the anode.

grid used -in this way is commonly known as a space charge grid; 'Thepurpose of this grid is to lower the impedance between the cathode andanode, and for this purpose the grid has ordinarily been maintained at aconstant positive potential. .It

- has been observed, however, that the curv rent flowing from .thisspacecharge grid varies in the opposite way from the man ner in whichthecurrent to the anode varies when acted upon by the control grid. Thatis, as the current to the 'anodeincreases the f and vice versa.

, the space 0 current to the space charge grid decreases, If animpedance is placed in'circuit with arge grid the vcurrent variations 3am the circuit of the space charge grid will 40 charge 4 cause thepotential of the space charge-grid to vary.

, 'A'more specific object of myinvention is to produc dpotentialvariations of the space i which will act upon the controlfgri throughthe ca acity existing between the two grids, and commonly'known' .as aregenerative efi'ect,

thereb increasing the amount of amplifica-f 46 tionw ich can be producedby means. of the tube.

It has "'be en prop osed iniVan der Bijl .Patent 1,479,779 to provide aninductive feed-back coupling- 'betweenthe circuit of 5Q the space chargegrid and the circuit of the control grid and produce regeneration inthis way. In this case the direction of the coupling between the twocircuits must be produce. what is Application filed May 29, 1924. Serial170. 716,821.

arranged in the opposite manner to that of three-electrode device, -byreason of the capacitycoupling between 'the' plate and grid, when theplate. circuit is *properly tuned, the usual adjustment of the platecircuit employed in this case is not suitable for the adjustment of thecircuit of the space.

charge grid in the fo ur;electrode device because of'the fact, aspointed out above, that the current in the two circuits vary in oppositedirections. I have discovered that thedesired feed-back through'thecapacity between the twoxgrids may be obtained ifv the impedance of thespace charge "grid'has a suitable capacity rea'ctance. The novelfeatures which I believe to be characteristic of myinvention are setforth with particularity in the appended claims,

my invention itself, however, both as to its organization and method ofoperation will best be understoodby reference to the fol-' lowingdescription taken in connection with the accompanying drawing 1 and 2show diagrammatically-two difi'erent circuit arrangements which may beemployed for carrying my inve'ntion into efect. i I have indicated inthe drawing the application of my invention to the reception anddetection of radio signals. I have shown in the drawing an electrondischarge device 1 having themsual electron emitting, cathode in whichFigs.

2, anode 3, control grid 4, and space charge grid 5. Signals from theantenna 6 are impressed upon the circuit of the control gr d in theusual manner. The space charge grid 5 is connected by a suitable tap 7to the battery 8, which supplies the necessary plate potential for theoperation of the device. I

In Fig. 1 I have shown in the circuit of the space charge grid avariable inductance 9 and variable capacity 10 in parallel. By suitableadjustment of these impedances the desired regenerative effect may beobtained. I have found that the adjustment of the circuit is notespecially critical as when it has once been adjustedto a sensitive.point it is still sensitive over a considerable range of wave lengths.It does not require readjustment every time that the tuning of the inputcircuit is changed.

The arrangement of Fig. 2 diifers from that of Fig. 1 only in that theentire adjustment of the circuit of the space charge grid isaccomplished by means of a variomcter 11. I. have found-that the naturalcapacity of the variomcter, which I have in dicated by a shunt condenser12, is in some cases sufi'icient to produce the proper adjustment of thephase relation of the potential of the space charge grid with respect tothat of the control grid to produce the desired regeneration.

\Vhile I have shown and described only two modifications of myinvention, it is evident that the phase of the potential of the spacecharge grid with respect to that of the control grid may be adjusted invarious other ways to secure the desired result and that my inventionmaybe cmploycd with any type of circuit connection in which regenerativeamplification is desired.

- What I claim as new and desire to secure by Letters Patent of theUnited States, is

1. An amplifying apparatus comprising an electron discharge devicehaving an electron emitting cathode, an anode and two grids interposedbetween cathode and anode.

circuit connections between the cathode and each of the otherelectrodes, means for supplying electrical variations to be amplified tothe circuit between the cathode and the grid nearest the anode, meansfor producing resultant variations of the potential of the grid nearestthe cathode, and means for ad' justing the phase of the resultantvariations in the potential of the grid nearest the cathode to producean increased amplification.

2. An amplifying apparatus comprising an electron discharge devicehaving an electron emitting cathode, an anode and two grids interposedbetween cathode and anode, circuit connections between the cathode andeach of the other electrodes, means for supplying electrical variationsto be amplified to the circuit between the cathode and the grid nearestthe anode, means for producing resultant variations of thepotential ofthe grid nearest the cathode, and means for adjusting the phase of theresultant variations in the potential ofthe grid nearest the cathode toproduce an increased amplification by reason of the capacity relationsbetween the two grids. I 3. An amplifying apparatus comprising anelectron discharge device having an elec tronemitting cathode, an anode,and two grids interposed between cathode and anode, circuit connectionsbetween the cathode and each of the other electrodes, means forsupplying electrical variations to be amplified to the circuit'betweenthe cathode and the grid nearest the anode, and means for producing aregenerative effect by reason of the capacity relations between the twogrids, and thereby increasing the amplification.

4. An amplifying apparatus comprising an electron discharge devicehaving an electron emitting cathode, an anode and two grids'interposedbetween cathode and anode, circuit connections between the cathode andeach of the other electrodes, means for supplying electrical variationsto be amplified to the circuit between the cathode and the grid nearestthe anode, and nicans for iinpressing upon the grid nearest the anodethrough the capacity between the two grids electrical variationssubstantially in phase with those originally supplied thereto.

In witness whereof, I have hereunto set my hand this 28th day of May1924.

" STEWART L. CLOTHIER.

